Hello,

I realize that I have not given any guidance as to using the log
files from LTRDump.  I find users tend not to have a good idea
of what a good decode looks like and it is my fault.

Occasionally noise can be decoded as a valid frame so a single
frame does not really mean anything.  Some versions like beta
ec2 had bugs that caused frames of all zeros being logged.
You need to look for patterns.

I can not stress the need for a clean signal too much.  Any
noise increases the chance of it causing errors or being
mistaken for valid data.  You need to use a slicer with a
low pass filter to filter out the voice.  The program should
decode while there is voice on the channel.

I found the lack of a time stamp to be a problem with logging.
Are those two frames adjacent or hours apart?  It also allows
judging the signal quality as you can judge the number of
frames per second.

Regular LTR

The rate of Regular LTR is slightly over 7 frames per second.
If the program is decoding 100 percent there will be 7 frames
each second of log time with a occasional 8 frames a second
of log time.  If you were listening to 471.8875 in Boston on
the date and time indicated you might have logged:

========================
Thu May  6 20:26:16 2004           Dumper Version  5-May-2004
========================
229240bd Area:0  Ch  1 Free  Ch 17 Active -> User: 0-9-36
1290760d Area:0  Ch 12 Free  Ch  9 Active -> User: 0-9-7
1a903190 Area:0  Ch  3 Free  Ch 13 Active -> User: 0-9-3
229240bd Area:0  Ch  1 Free  Ch 17 Active -> User: 0-9-36
12907400 Area:0  Ch  8 Free  Ch  9 Active -> User: 0-9-7
1a903190 Area:0  Ch  3 Free  Ch 13 Active -> User: 0-9-3
2292466a Area:0  Ch 12 Free  Ch 17 Active -> User: 0-9-36
========================
Thu May  6 20:26:17 2004           Dumper Version  5-May-2004
========================
12907400 Area:0  Ch  8 Free  Ch  9 Active -> User: 0-9-7
1a903097 Area:0  Ch  1 Free  Ch 13 Active -> User: 0-9-3
1290760d Area:0  Ch 12 Free  Ch  9 Active -> User: 0-9-7
1a903190 Area:0  Ch  3 Free  Ch 13 Active -> User: 0-9-3
129078eb Area:0  Ch 17 Free  Ch  9 Active -> User: 0-9-7
129071dd Area:0  Ch  3 Free  Ch  9 Active -> User: 0-9-7
129076ce Area:0  Ch 13 Free  Ch  9 Active -> User: 0-9-7
129070da Area:0  Ch  1 Free  Ch  9 Active -> User: 0-9-7
========================
Thu May  6 20:26:18 2004           Dumper Version  5-May-2004
========================
1290760d Area:0  Ch 12 Free  Ch  9 Active -> User: 0-9-7
3e9074ba Area:0  (Extended) Ch  9 Unkey -> User: 0-9-7
129071dd Area:0  Ch  3 Free  Ch  9 Active -> User: 0-9-7
1290760d Area:0  Ch 12 Free  Ch  9 Active -> User: 0-9-7
========================
Thu May  6 20:26:19 2004           Dumper Version  5-May-2004
========================
129070da Area:0  Ch  1 Free  Ch  9 Active -> User: 0-9-7

The segment starts out with 3 talkgroups active with group
0-9-7 on repeater 9, 0-9-3 on repeater 13, and 0-9-36 on
repeater 17.  In short order the users unkey.  At 20:26:18
the last user unkeys and another user in the group quickly
keys up.

You can see this system has an unusual repeater number
configuration with 1, 3, 8, 9, 12, 13, and 17.

Multi-Net LTR

The rate of Multi-Net LTR is between 4 and 5 frames per second.
If the program is decoding 100 percent there will be 4 frames
each second of log time alternating with 5 frames a second
of log time.  This is an example of a idle Multi-Net LTR
status channel.

========================
Thu May  6 21:14:34 2004           Dumper Version  5-May-2004
========================
155c8b377b0b36a Multinet -> 61a87fc38fffc25 LCN    56 Free  LCN    53 Idle (Ch  1)
155c8b377b0b36a Multinet -> 61a87fc38fffc25 LCN    56 Free  LCN    53 Idle (Ch  1)
155c8b377b0b36a Multinet -> 61a87fc38fffc25 LCN    56 Free  LCN    53 Idle (Ch  1)
155c8b378b0b324 Multinet -> 61a87fc37fffc6b LCN    55 Free  LCN    53 Idle (Ch  1)
========================
Thu May  6 21:14:35 2004           Dumper Version  5-May-2004
========================
155c8b378b0b324 Multinet -> 61a87fc37fffc6b LCN    55 Free  LCN    53 Idle (Ch  1)
155c8b378b0b324 Multinet -> 61a87fc37fffc6b LCN    55 Free  LCN    53 Idle (Ch  1)
155c8b376b0b375 Multinet -> 61a87fc39fffc3a LCN    57 Free  LCN    53 Idle (Ch  1)
155c8b379b0b33b Multinet -> 61a87fc36fffc74 LCN    54 Free  LCN    53 Idle (Ch  1)
155c8b377b0b36a Multinet -> 61a87fc38fffc25 LCN    56 Free  LCN    53 Idle (Ch  1)
========================
Thu May  6 21:14:36 2004           Dumper Version  5-May-2004
========================
155c8b378b0b324 Multinet -> 61a87fc37fffc6b LCN    55 Free  LCN    53 Idle (Ch  1)
155c8b379b0b33b Multinet -> 61a87fc36fffc74 LCN    54 Free  LCN    53 Idle (Ch  1)
155c8b376b0b375 Multinet -> 61a87fc39fffc3a LCN    57 Free  LCN    53 Idle (Ch  1)
155c8b379b0b33b Multinet -> 61a87fc36fffc74 LCN    54 Free  LCN    53 Idle (Ch  1)
========================
Thu May  6 21:14:37 2004           Dumper Version  5-May-2004
========================
155c8b378b0b324 Multinet -> 61a87fc37fffc6b LCN    55 Free  LCN    53 Idle (Ch  1)

Multi-Net LTR uses xor masks for system security.  The log gives the original and
the translated data.  They should be different.  Multinet uses direct goto LCNs
but the repeater numbers are still specified.  Repeater one is LCN 53 which is
935.6625 and the system alao uses 935.675, 935.6875, 935.7000, and 935.7125.

Here is a radio 2123 keying up on group 2-232.

155c8b376b0b375 Multinet -> 61a87fc39fffc3a LCN    57 Free  LCN    53 Idle (Ch  1)
155c4ef770d13db Multinet -> 61a8ba038425c94 LCN    56 Free  LCN    53 Active -> Group: 2-232 User 2123
========================
Thu May  6 21:28:58 2004           Dumper Version  5-May-2004
========================
155c4ef760d13c4 Multinet -> 61a8ba039425c8b LCN    57 Free  LCN    53 Active -> Group: 2-232 User 2123
155c4ef760d13c4 Multinet -> 61a8ba039425c8b LCN    57 Free  LCN    53 Active -> Group: 2-232 User 2123
155c4ef770d13db Multinet -> 61a8ba038425c94 LCN    56 Free  LCN    53 Active -> Group: 2-232 User 2123
155c4ef790d138a Multinet -> 61a8ba036425cc5 LCN    54 Free  LCN    53 Active -> Group: 2-232 User 2123
========================

Passport

The rate of Passport LTR is between 4 and 5 frames per second.
If the program is decoding 100 percent there will be 4 frames
each second of log time alternating with 5 frames a second
of log time.  The idle bursts of a passport system are what
I call "Neighbor" frames and usually occurs every two seconds.

========================
Thu May  6 21:37:41 2004           Dumper Version  5-May-2004
========================
1c0630a8a8c57b2 Passport  Neighbor -> DCC: 0 LCN 1111 c:1793 g:70-5397
========================
Thu May  6 21:37:43 2004           Dumper Version  5-May-2004
========================
1c0630a8a8c4693 Passport  Neighbor -> DCC: 0 LCN 1094 c:1793 g:70-5397
========================
Thu May  6 21:37:45 2004           Dumper Version  5-May-2004
========================
52ffffff *revcrc Area:1  (Unknown) C: 9 H:15 G:255 F:31
1c0630a8a88e040 Passport  Neighbor -> DCC: 0 LCN  224 c:1793 g:70-5397
19264905b4f2360 Multinet -> 19264905b4f2360 LCN    91 Free  LCN   804 Active -> Group: 25-36 User 2532
========================
Thu May  6 21:37:49 2004           Dumper Version  5-May-2004
========================
0e0318545447020 Multinet -> 0e0318545447020 LCN   325 Free  LCN   448 Active -> Group: 12-97 User 2190
========================
Thu May  6 21:37:51 2004           Dumper Version  5-May-2004
========================
1c0630a8a8c57b2 Passport  Neighbor -> DCC: 0 LCN 1111 c:1793 g:70-5397
========================
The DCC (Area) of this system is zero.  The 70 is the site id and 5397
is a system configuration word.  The LCN are goto frequencies for
neighboring sites.  This is a 450 to 470 MHz system so 91 is 451.1375,
224 is 452.8000, 1094 is 463.675, and 1111 is 463.8875.

You can also see some noise affecting the decoding at 21:37:45 and 21:37:49
with the burst at 21:37:47 missing.  The Regular LTR and Multinet packets
are not valid.

Here is Mobile ID 2251 of site 40 talking on group 62047.

========================
Tue Mar  9 21:33:44 2004           Dumper Version 06-Mar-2004
========================
014d4792f839fa1 Passport  LCN   927 Free  LCN    83 Active -> Group: 40-62047
014d40465b06154 Passport  LCN    97 Free  LCN    83 Active -> MID: 40-2251
000ad4792f80e969 Multinet *badpar (0001) 
014d4792f839fa1 Passport  LCN   927 Free  LCN    83 Active -> Group: 40-62047
014d4792f80617b Passport  LCN    97 Free  LCN    83 Active -> Group: 40-62047
========================
Tue Mar  9 21:33:45 2004           Dumper Version 06-Mar-2004
========================
014d4792f80e969 Passport  LCN   233 Free  LCN    83 Active -> Group: 40-62047
014d4792f839fa1 Passport  LCN   927 Free  LCN    83 Active -> Group: 40-62047
014d4792f80617b Passport  LCN    97 Free  LCN    83 Active -> Group: 40-62047
014d4792f80e969 Passport  LCN   233 Free  LCN    83 Active -> Group: 40-62047
========================
Tue Mar  9 21:33:46 2004           Dumper Version 06-Mar-2004
========================
014d4792f839fa1 Passport  LCN   927 Free  LCN    83 Active -> Group: 40-62047
014d40465b06154 Passport  LCN    97 Free  LCN    83 Active -> MID: 40-2251
1c0190a8a8c4893 Passport  Neighbor -> LCN  1096 c:1792 g:50-5397
014d4792f80e969 Passport  LCN   233 Free  LCN    83 Active -> Group: 40-62047
========================
Tue Mar  9 21:33:47 2004           Dumper Version 06-Mar-2004
========================
014d4792f839fa1 Passport  LCN   927 Free  LCN    83 Active -> Group: 40-62047
014d4792f80617b Passport  LCN    97 Free  LCN    83 Active -> Group: 40-62047
014d4792f80e969 Passport  LCN   233 Free  LCN    83 Active -> Group: 40-62047
1ffd4792f885302 Passport  LCN    83 Free  Unkey -> Group: 40-62047
1c0590a8a8c5b03 Passport  Neighbor -> LCN  1115 c:1793 g:50-5397
========================

The Multinet frame is not valid and likely a bad Passport LTR frame.
Ocassionally the Mobile ID and neighbor information is sent.
The mobile is talking on 451.0375 at site 50 (Wolcott, CT).  Site 50
also has 451.2125 (97), 452.9125 (233), and 461.5875 (927).

73 Eric